Sets the text of the tooltip to be @markup, which is marked up with the [Pango text markup language]PangoMarkupFormat. If @markup is %NULL, the label will be hidden.
a markup string (see [Pango markup format]PangoMarkupFormat) or %NULL
2.12
See Implementation
Sets the text of the tooltip to be @markup, which is marked up with the [Pango text markup language]PangoMarkupFormat. If @markup is %NULL, the label will be hidden.